asfdemux: Handle EOS in push-mode on corrupted files
asfdemux: Handle EOS in push-mode on corrupted files

It is possible no streams were activated when receiving EOS, if so
handled it as if we hadn't seen the header

https://bugzilla.gnome.org/show_bug.cgi?id=774846

GStreamer/gst-plugins-ugly,GrokImageCompression/gst-plugins-ugly,GStreamer/gst-plugins-ugly,GrokImageCompression/gst-plugins-ugly,StreamUtils/gst-plugins-ugly,StreamUtils/gst-plugins-ugly,GrokImageCompression/gst-plugins-ugly,GStreamer/gst-plugins-ugly,StreamUtils/gst-plugins-ugly